Prior to 2015, Zika virus (ZIKV) was suspected of causing little more than an asymptomatic illness termed Zika fever (also known as Zika virus disease), sometimes characterized by fever, red eyes, joint pain, headache, and a rash that resolved within seven days. The virus was first discovered in 1947 and named after the Zika forest in Uganda, although the first human case was not reported until 1952. The virus is primarily transmitted to humans following a bite by an infected mosquito of the Aedes genus, most commonly by the mosquito species A. Aegypti and A. Albopictus, which are primarily found in tropical and subtropical zones throughout the world. Since it was discovered in 1947, ZIKV has spread beyond Uganda and across Africa, and by the early 1980s the virus had reached Asia; however given the mild nature of the disease, only 14 cases of ZIKV infection were reported prior to 2007.
ZIKV began to attract global attention in 2013, when outbreaks were reported in four groups of Pacific islands: French Polynesia, Easter Island, the Cook Islands, and New Caledonia. Retrospective investigations of these outbreaks indicated a possible association between ZIKV infection in pregnant women and congenital malformations in newborns (Cauchemez et al., Lancet, 387:2125-2132 (2016)), including severe neurological and autoimmune complications. The virus was also found in semen (Musso et al., Emerg Infect Dis, 21:359-361 (2015)), and in blood donations from asymptomatic donors (Musso et al., Euro Surveill, 19:20761 (2014), Chan et al., J Infect, 72:507-524 (2016)), suggesting that the virus could be transmitted through sexual contact and blood transfusions.
In March 2015, an outbreak of ZIKV was reported in Brazil; nearly 7000 cases were documented between February and April of that year, which represented the first documented report of locally-acquired ZIKV in the Americas. The virus has continued to spread throughout South America, Central America, and the Caribbean islands. Although still characterized as a mild disease, in October 2015, Brazil noticed an alarming increase in the number of cases of microcephaly since August 2015. Microcephaly is a medical condition in which the brain of a developing fetus does not form properly, resulting in a smaller than normal head, and often long-term mental and developmental disabilities. By November 2015, Brazil declared a national public health emergency as the number of suspected microcephaly cases continued to rise. A January 2016 study conducted by health officials in Brazil and the United States Centers for Disease Control and Prevention (CDC) provided the strongest evidence to date of an association between ZIKV infection and microcephaly (see, e.g., U.S. Centers for Disease Control and Prevention website, Oliveira et al, Ultrasound Obstet Gynecol, 18:167-168 (2016) and Schuler-Faccini et al., MMWR Morb Mortal Wkly Rep, 65:59-62 (2016)). Zika infection has also been proposed to cause Guillain-Barré syndrome (GBS), in which an autoimmune response is triggered that damages the nervous system (van den Berg et al., Ned Tijdschr Geneeskdi, 160: D155 (2016), Cao-Lormeau et al., Lancet, 387:1531-1539 (2016)).
No vaccine exists against ZIKV, and no therapeutics are available. In March of 2015, the World Health Organization (WHO) officially declared ZIKV infection a Public Health Emergency of International Concern (PHEIC) among mounting evidence linking ZIKV infection during pregnancy to microcephaly in newborns. Rapid technological advancements are required to accurately diagnose and combat the spread of this virus.
There exists an urgent need for compositions and methods to identify not only individuals infected with ZIKV, but also to screen blood supplies that may unknowingly contain the virus. The invention provides such compositions and methods.